Ras,
I'm currently using both TS HD and DishTru HD. TS STB is connected to a 42 inch LED TV and Dish TV is connected to a 32 inch LED TV.
Comparing the HD channels PQ, it almost looks same. But most of the TS HD channels are DD+. But you will not notice any difference even if the Audio output is connected to a 5.1 speaker system.
Regarding SD channels;
The SD channel PQ is really pathetic on Dish TV compared to TS. As I said, I'm using 32 inch LED tv with Dish TV. Still the PQ of SD channels (most of the channels ) on 32 inch TV is not good. Coming to TS, the PQ of the SD channels on TS is much better even on the 42 inch TV.
TS would be more expensive compared to DishTV. If you don't compromise with good PQ and AQ, then go with TS for sure. If you prefer more channels with low price, then Dish TV would be the best choice (but don't regret seeing the PQ of SD channels).
Let me know if you need any further clarifications on the same.
Note: I'm currently planning to deactivate the DishTv connection.